One-Step Hydrothermal Synthesis of (NH4)2V4O9 Thin Films Composed of Stacked Single-Crystal Nanosheets

2017 ◽  
Vol 863 ◽  
pp. 102-106
Author(s):  
Xue Mei Yang ◽  
Xiao Yu Zhou ◽  
Zhong Ping Liu ◽  
Lan Xiang Ji ◽  
Jian Guo Deng
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Band Gap ◽  
Oriented Attachment ◽  
Practical Applications ◽  
Crystal Growth Mechanism ◽  
Potential Applications ◽  
One Step ◽  
Vertically Aligned ◽  
Defect Densities

(NH4)2V4O9 thin films composed of vertically aligned single-crystal nanosheets were directly fabricated on quartz glass by a one-step hydrothermal method. In order to study the formation mechanism and to explore the potential applications of the thin films, process experiments were carried out and the band gap was analyzed. An oriented-attachment exfoliation–recrystallization–crystal growth mechanism was proposed for the formation of the (NH4)2V4O9 thin films. In addition, the band gap varied from 2.13 to 2.87 eV with variations in the thickness from 40.21 to 78.64 μm. The move of the band gap main due to the decreasing bond lengths and defect densities with increasing reaction time and which is significant for practical applications.

Single Crystal, High Band Gap CdS Thin Films Grown by RF Magnetron Sputtering in Argon Atmosphere for Solar Cell Applications

2018 ◽  
Vol 10 (3) ◽  
pp. 03005-1-03005-6 ◽  
Author(s):  
Rupali Kulkarni ◽  
◽  
Amit Pawbake ◽  
Ravindra Waykar ◽  
Ashok Jadhawar ◽  
...  
Keyword(s):  
Thin Films ◽  
Solar Cell ◽  
Magnetron Sputtering ◽  
Single Crystal ◽  
Band Gap ◽  
Rf Magnetron Sputtering ◽  
Argon Atmosphere ◽  
Cds Thin Films ◽  
High Band

Spray Chemical Vapor Deposition of CuInS2 Thin Films for Application in Solar Cell Devices

1997 ◽  
Vol 495 ◽  
Author(s):  
Jennifer A. Hollingsworth ◽  
William E. Buhro ◽  
Aloysius F. Hepp ◽  
Philip P. Jenkins ◽  
Mark A. Stan
Keyword(s):  
Thin Films ◽  
Chemical Vapor Deposition ◽  
Band Gap ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Fused Silica ◽  
Direct Band Gap ◽  
Cuins2 Thin Films ◽  
Potential Applications ◽  
Direct Band

ABSTRACTChalcopyrite CuInS2 is a direct band gap semiconductor (1.5 eV) that has potential applications in photovoltaic thin film and photoelectrochemical devices. We have successfully employed spray chemical vapor deposition using the previously known, single-source, metalorganic precursor, (Ph3P)2CuIn(SEt)4, to deposit CuInS2 thin films. Stoichiometric, polycrystalline films were deposited onto fused silica over a range of temperatures (300–400 °C). Morphology was observed to vary with temperature: spheroidal features were obtained at lower temperatures and angular features at 400 °C. At even higher temperatures (500 °C), a Cu-deficient phase, CuIn5S8, was obtained as a single phase. The CuInS2 films were determined to have a direct band gap of ca. 1.4 eV.

scholarly journals Temperature-dependent optical and vibrational properties of PtSe2 thin films

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Desman P. Gulo ◽  
Han Yeh ◽  
Wen-Hao Chang ◽  
Hsiang-Lin Liu
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Room Temperature ◽  
Near Infrared ◽  
Technological Development ◽  
Phonon Modes ◽  
Research Attention ◽  
Practical Applications ◽  
Infrared Frequency Range ◽  
Indirect Band Gap

Abstract PtSe2 has received substantial research attention because of its intriguing physical properties and potential practical applications. In this paper, we investigated the optical properties of bilayer and multilayer PtSe2 thin films through spectroscopic ellipsometry over a spectral range of 0.73–6.42 eV and at temperatures between 4.5 and 500 K. At room temperature, the spectra of refractive index exhibited several anomalous dispersion features below 1000 nm and approached a constant value in the near-infrared frequency range. The thermo-optic coefficients of bilayer and multilayer PtSe2 thin films were (4.31 ± 0.04) × 10−4/K and (–9.20 ± 0.03) × 10−4/K at a wavelength of 1200 nm. Analysis of the optical absorption spectrum at room temperature confirmed that bilayer PtSe2 thin films had an indirect band gap of approximately 0.75 ± 0.01 eV, whereas multilayer PtSe2 thin films exhibited semimetal behavior. The band gap of bilayer PtSe2 thin films increased to 0.83 ± 0.01 eV at 4.5 K because of the suppression of electron–phonon interactions. Furthermore, the frequency shifts of Raman-active Eg and A1g phonon modes of both thin films in the temperature range between 10 and 500 K accorded with the predictions of the anharmonic model. These results provide basic information for the technological development of PtSe2-based optoelectronic and photonic devices at various temperatures.

Controlled Growth of High-Temperature Superconducting Thin Films on Polycrystalline Substrates

MRS Bulletin ◽  
1992 ◽  
Vol 17 (8) ◽  
pp. 39-44 ◽  
Author(s):  
David T. Shaw
Keyword(s):  
Thin Films ◽  
High Temperature ◽  
Single Crystal ◽  
Technology Development ◽  
Magnetic Energy ◽  
High Quality ◽  
Practical Applications ◽  
High Temperature Superconducting ◽  
Controlled Processing ◽  
Crystal Films

Since their discovery in 1987, significant progress has been made in the fabrication of high-quality, high-temperature superconducting (HTS) thin films. Films with reproducible properties can be routinely deposited on single crystal substrates by several well-established processing techniques. Single crystal substrates, however, are not suitable for many applications because of their cost, limitations in size and shape, and lack of flexibility. Hence, a great deal of effort has been directed at the fabrication of thin films on polycrystalline rather than single crystal substrates. For example, metallic substrates are expected to be useful for the fabrication of HTS conductors for such applications as generators, motors, and superconducting magnetic energy storage (SMES) devices. For polycrystalline thin-film applications, lattice matching for epitaxial growth of thin films is no longer possible. Microstructures of these films are generally more complex than those of single crystal films, primarily because of grain boundaries. As a result, the microstructure of polycrystalline films must be carefully controlled to ensure that the critical current density is high enough for practical applications.Happily, progress in this respect has been substantial. There have been laboratory demonstrations of techniques for controlled processing of high-quality HTS thin films on polycrystalline substrates. Even though the technology development in this area is still in its infancy, many successful processing approaches have been developed to set the stage for the eventual use of HTS thin films in power device applications.

Synthesis of narrow band gap SnTe nanocrystals: nanoparticles and single crystal nanowires via oriented attachment

CrystEngComm ◽  
2010 ◽  
Vol 12 (12) ◽  
pp. 4275 ◽  
Author(s):  
Jiajia Ning ◽  
Kangkang Men ◽  
Guanjun Xiao ◽  
Bo Zou ◽  
Li Wang ◽  
...  
Keyword(s):  
Single Crystal ◽  
Band Gap ◽  
Narrow Band ◽  
Oriented Attachment

Structure, band gap, and Mn-related mid-gap states in epitaxial single crystal (Zn1−xMgx)1−yMnyO thin films

2013 ◽  
Vol 113 (17) ◽  
pp. 173701
Author(s):  
Dapeng Zhu ◽  
Guolei Liu ◽  
Shuqin Xiao ◽  
Shishen Yan ◽  
Shumin He ◽  
...  
Keyword(s):  
Thin Films ◽  
Single Crystal ◽  
Band Gap ◽  
Gap States

One-step electrodeposition of CuInxGa1−xSe2 thin films from a mixture system of ionic liquid and ethanol

2015 ◽  
Vol 39 (10) ◽  
pp. 7742-7745 ◽  
Author(s):  
Ye Lian ◽  
Shanshan Ji ◽  
Lei Zhao ◽  
Jie Zhang ◽  
Peixia Yang ◽  
...  
Keyword(s):  
Thin Film ◽  
Thin Films ◽  
Ionic Liquid ◽  
Band Gap ◽  
High Crystalline Quality ◽  
Cigs Thin Film ◽  
Type Semiconductor ◽  
One Step ◽  
P Type ◽  
Mixture System

Synthesizing high crystalline quality p-type semiconductor CIGS thin film with a band gap of 1.41 eV by galvanostatic electrodeposition.

Nanostructured A2(RE,B)O6 (A = Ba, Sr; RE = Rare-Earth; B = Sb, Zr) Perovskite Ceramics and their Potential Applications in Microwave and Superconducting Electronics

2012 ◽  
Vol 545 ◽  
pp. 27-31 ◽  
Author(s):  
P.R.S. Wariar ◽  
V.R. Kumar ◽  
V.M. Nair ◽  
M.M. Yusoff ◽  
R. Jose ◽  
...  
Keyword(s):  
Rare Earth ◽  
Band Gap ◽  
Wide Band ◽  
Wide Band Gap ◽  
Practical Applications ◽  
Ceramic Superconductors ◽  
Low Dielectric ◽  
Potential Applications ◽  
Wide Band Gap Semiconductors ◽  
Perovskite Lattice

A group of perovskites with general formula A2(RE,B)O6(A=Ba, Sr; RE=Rare-Earth; B=Sb, Zr) were synthesized as nanocrystals owing to the enhanced specific surface area that nanomaterials posses. These perovskites are characterized by varied crystal structure depends on the relative sizes of the cations occupying the A and B sites of the perovskite lattice. The new materials were either insulators or semiconductors. They possess moderate dielectric constant (~30) and relatively low dielectric loss (10-4); and therefore, they could be used as substrates in microwave circuits. Some of them falls to the semiconducting range with band gap ~3.3 eV; and therefore, could be used as transparent wide band gap semiconductors. Furthermore, the new perovskites were found to be chemically stable with two mostly considered high temperature ceramic superconductors for practical applications, viz. YBa2Cu3O7-δ(YBCO) and (Bi,Pb)2Sr2Ca2Cu3Ox(BSCCO).

scholarly journals Sol-Gel Derived Cds Nanocrystalline Thin Films: Optical and Photoconduction Properties

2018 ◽  
Vol 36 (2) ◽  
pp. 235-241 ◽  
Author(s):  
Ziaul Raza Khan ◽  
Anver Aziz ◽  
Mohd. Shahid Khan ◽  
Keyword(s):  
Thin Films ◽  
Band Gap ◽  
Sol Gel ◽  
Hexagonal Wurtzite Structure ◽  
Solution Temperature ◽  
Nanocrystalline Phase ◽  
Glass Substrates ◽  
Coating Method ◽  
Potential Applications ◽  
Nanocrystalline Thin Films

Abstract High-quality CdS nanocrystalline thin films were grown by sol-gel spin coating method at different solution temperatures on glass substrates. As-deposited films exhibited nanocrystalline phase with hexagonal wurtzite structure and showed good adhesion and smooth surface morphology. It was clearly observed that the crystallinity of the thin films improved with the increase in solution temperature. Crystallites sizes of the films also increased and were found to be in the range of 10 mm to 17 nm. The influence of the growth mechanism on the band and sub-band gap absorption of the films was investigated using UV-Vis and photothermal deflection spectroscopy (PDS). The band gap values were calculated in the range of 2.52 eV to 2.75 eV. The band gap decreased up to 9 % with the increase in solution temperature from 45 °C to 75 °C. Absorption coefficients estimated by PDS signal showed the significant absorption in low photon energy region of 1.5 eV to 2.0 eV. The dark and illuminated I-V characteristics revealed that the films were highly photosensitive. The results demonstrated the potential applications of sol-gel grown CdS nanocrystalline thin films as photoconductors and optical switches.

Self-assembled vertically aligned Ni nanopillars in CeO2 with anisotropic magnetic and transport properties for energy applications

Nanoscale ◽  
2018 ◽  
Vol 10 (36) ◽  
pp. 17182-17188 ◽  
Author(s):  
Jijie Huang ◽  
Zhimin Qi ◽  
Leigang Li ◽  
Han Wang ◽  
Sichuang Xue ◽  
...  
Keyword(s):  
Thin Films ◽  
Metal Oxide ◽  
Transport Properties ◽  
Energy Applications ◽  
Nanocomposite Thin Films ◽  
Growth Method ◽  
One Step ◽  
Vertically Aligned ◽  
Step Growth ◽  
Self Assembled

Self-assembled vertically aligned metal–oxide (Ni–CeO2) nanocomposite thin films with novel multifunctionalities have been successfully deposited by a one-step growth method.

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